Effect of dawri‐damaa (Pentas schimperiana) leaf meal supplementation on performances, carcass characteristics, and economic feasibility of sheep fed native grass hay

Abstract With a growing export and local market, sheep farming is critical to the economy of smallholder farmers; however, indigenous sheep breeds usually exhibit low carcass output and live weight due to nutritional constraints. The study aimed to investigate the impact of supplementing local sheep with dawri‐damaa leaf meal (DDLM) on their performance, carcass characteristics, and profitability when fed native grass hay. The research used a randomized complete block design (RCBD) to administer four feeding treatments (T1, T2, T3, and T4 at 0%, 30%, 50%, and 70% DDLM, respectively) to 20 local uncastrated male lambs having an average 23.72 ± 0.73 kg body weight and average age of 11.72 ± 0.74 months. Greater doses of DDLM in the diet resulted in greater average daily gain (ADG) of 51.4–83.8 g/day and feed conversion efficiency (FCE) of 0.066–0.089 in lambs, compared to 15.0 g/day ADG and 0.025 FCE in lambs under control diet (T1). Additionally, the lambs had increased slaughter body weight (SBW), empty body weight (EBW), and hot carcass weight (HCW) in T4 and T3 compared to other treatments (p < .05). There were no significant differences in dressing percentages (DPs) across any treatment group. The study also discussed the economic viability of supplementing with DDLM, suggesting that feeding 70% daily dry matter of DDLM at 2.5% live weight might be beneficial depending on availability, access, and cost factors. In conclusion, feeding DDLM up to 70% has improved the performance of sheep and is economically feasible. Further research might be required to discover whether such levels of inclusion are harmful and apply different processing methods for feeding animals.

Globalization is reshaping the lamb meat market, influenced not only by customs and traditions but also by increasing consumer awareness regarding food product origins and associated quality aspects (Erasmus et al., 2017).While sheep raised in feedlots often show improved carcass weight, there is a noted decrease in meat quality (Hou et al., 2023;Luo et al., 2019;Wang et al., 2018).Optimal use of grasslands is an effective means of converting energy into food, making grazing systems a pivotal component in the rapidly growing global lamb meat production.Ethiopia, home to the secondlargest sheep population in Africa, primarily relies on natural grassland grazing within its production system, which is low in nutritional value.
Ethiopia's sheep breeds are highly sought-after in the Middle East due to their taste and the organic nature of their production (Animut & Wamatu, 2014).The primary destinations for Ethiopia's sheep and goat meat exports include the United Arab Emirates, Saudi Arabia, Qatar, Oman, and Kuwait (OEC, 2021;USAID, 2021).
In 2021, Ethiopia recorded $93.9 million in sheep and goat meat exports, ranking as the 10th largest exporter of sheep and goat meat globally, and marking it as the 9th most exported product from Ethiopia in the same year (OEC, 2021).
Local sheep typically demonstrate poor carcass output and limited live weight gain, averaging 50 g per animal daily for meat production (Melaku & Betsha, 2008).Moreover, the average lamb carcass weight of 10 kg falls below the global average of 15.8 kg (FAO, 2013).Nutrition plays a crucial role in addressing these challenges, as it is considered one of the most difficult production elements contributing to the subsector's low output (Getahun, 2015).
Moreover, the scarcity of feed resources during the dry season and the high prices for the limited available items jeopardize the economic viability of production systems (de Oliveira et al., 2018;Tikam et al., 2015).
Effective husbandry involves planning feed requirements for livestock farms, especially in traditional livestock production systems.Traditional methods lack precision and efficacy, and fundamental information is often unavailable or estimations are rough (Mekonnen et al., 2021).Feed deficiency is a common challenge, and animal weight loss is a common issue.
Increasing livestock output can be accomplished by supplementing locally available feedstuffs with graded quality concentrate feed, reducing scarcity through the introduction of improved local and hybrid forage grasses and legumes.The pursuit of geographically appropriate, less expensive, and more readily available components is one technique for producing carcasses with a differentiated quality pattern (de Oliveira et al., 2018).When compared to other animal products, ruminant meat production has a significant environmental cost, however, attempts to reduce the effect while increasing animal productivity have resulted in solutions (Salami et al., 2019).Farmers and the environment benefit from less feed required for the same or higher yield, demonstrating a clear advantage for livestock breeding and the planet (Gurgeira et al., 2022).
Traditional livestock production techniques typically rely on locally available resources with minimal opportunity costs.Pentas schimperiana, also known by the local name Dawri-damma, belongs to the Rubiaceae plant family.Its leaves and twigs provided animal feed, traditional medicinal value, and a source of income to the Dawuro community (Andarge et al., 2015;Tonamo et al., 2015;Woretaw et al., 2022).Feeding P. schimperiana to livestock is a popular nutritional technique in the community for increasing milk yield, improving carcass and meat quality, and benefiting the animal.
The plant is utilized in supplementing milk cows, dry cows, heifers, calves, oxen, bulls, sheep, goats, and equines.The study found that P. schimperiana might be used as supplementary feeds to enhance the utilization of low-quality feed resources and improve the performance of ruminants during the dry season when feed is scarce (Woretaw et al., 2022).
This study aimed to assess the influence of dawri-damaa leaf meal (DDLM) supplementation on feed efficiency, average daily gain, carcass characteristics, and the economic viability of local sheep fed hay grass in the Dawuro Zone of Southwestern Ethiopia.

| Study area
The study was conducted in the Mareka District of Dawuro Zone, Ethiopia, which is part of the Southern Nations, Nationalities, and Peoples' Region (SNNPR) state.The zone is bordered by the Gojeb and Omo rivers and is approximately 507 km from Addis Ababa.The field trial site was chosen in Waka Iyesus peasant administration, located 2 km west of Waka and 19 km southwest of Tercha.The annual mean minimum temperature in the zone is 14.9-26.4°C,with an annual mean rainfall range of 1200-1800 mm.The trial site is 2357 m above sea level and located at 70 8′ N latitude and 290 58′ E longitude.Among indigenous browse and legume plants preferred by farmers owning ruminants in the Dawuro Zone, dawri-damaa, cayshiya, and gasaa have greater nutritional value (Tonamo et al., 2015).
Another study indicated seasonal and agro-ecological variability of DM and CP contents of P. schimperiana.In the highland regions, Woretaw et al. (2022) showed 17.39% CP and 87.41% in vitro DM digestibility levels.However, our unpublished analysis showed that P. schimperiana had 90.2% DM, 17.74% CP, and 93.51% organic matter.Moreover, certain phytochemical studies suggested the existence of flavonoids, saponins, steroids, and tannins in P. schimperiana (Dinku et al., 2010;Kifle et al., 2022).Pentas schimperiana (A. Rich) Vatke (Rubiaceae) is widely used for the treatment of diabetes mellitus and various other ailments in the traditional medical practices of Ethiopia (Dinku et al., 2010).The methanolic leaf extract of P. schimperiana holds promise as a potential treatment for diabetes mellitus, especially in resource-limited settings (Amare et al., 2021).Heba-tollah et al. (2018) reported that Pentas species are commonly used in traditional medicine.

| Experimental animals, diets, and feeding
Using the dentition method and owner information, 20 yearling uncastrated male local Dawuro sheep with a mean initial live weight of 23.72 ± 0.73 kg and aged 11.72 ± 0.74 months (mean ± standard error (SE)) were obtained from the local market.The animal studies were approved by the Animal Experimentation Committee and followed the institutional norms of Jimma University's College of Agriculture and Veterinary Medicine.The experiment was carried out in accordance with recommendations made by the European Parliament and the Council of 22 September 2010 on the protection of animals used for scientific purposes.During the study, lambs were housed in pens measuring 1.55 m 2 each, with a floor area of 1 m 2 , a partition height of 1.4 m, a trough space of 0.12 m for ad libitum diets, and a trough space of 0.25 m for treatment meals.The floor spaces were bedded with dried enset (Ensete ventricosum) leaves and replaced on a regular basis based on the conditions.To allow for adaptation, the basal diet and 50 g dawri-damaa leaf meal (DDLM) were kept for a further seven days before data collection.Experimental feeds were composed of native grass hay as a basal diet and supplements of DDLM and ground maize.The experimental design was randomized complete block design (RCBD), with four treatments, one of which was control (T1).The experimental diets were weighed every morning before being distributed to the individual lambs in separate troughs and offered twice per day (DDLM) at 50% of their daily ration; in the morning and afternoon at 8:30 a.m. and 1:30 p.m., respectively, while ground maize (100 g) was offered once a day at 8:00 a.m.The supplements were adjusted to satisfy the maintenance needs of control lambs and then switched to meet the daily body gain (100 g/day) needs of lambs weighing 20-30 kg (ARC, 1980).Animals from each block were randomly assigned to one of the four treatment groups.
The DDLM supplement was given to treatments T1, T2, T3, and T4 at 0%, 30%, 50%, and 70%, respectively, based on daily dry matter intake rate of 2.5% of their live weight (McDonald et al., 2010), and was adjusted as body weight changed.All lambs were offered basal diets ad libitum, and 100 g of ground maize was supplemented to balance energy needs (Table 1).The well-being of the experimental animals was inspected and recorded twice a day, as specified by the Ethical Committee.The feeding trial lasted 90 days following quarantine and acclimatization to the experimental diet and pen.

| Body weight gain
The study involved taking two consecutive measurements following an overnight fast to ascertain the starting body weights of lambs.
Throughout the experiment, the weights were measured at 10-day intervals.The difference between final body weight and initial body weight was divided by the number of feeding days to get the average daily body weight gain (Abera et al., 2021).Feed conversion efficiency (FCE) was measured by dividing the lambs' mean daily weight gain by their daily DM consumption (NRC, 1996).

| Measures of carcass characteristics
The animals were stunned using procedures that caused no unnecessary pain, suffering, discomfort, or long-term harm to the animals after approval from Jimma University's Ethical Council.The animal was fed the experimental diet, DDLM, at the appropriate level and concentration, with no additives or negative effects introduced.
After 90 days of feeding, the sheep were fasted overnight and killed for carcass examination (Merhun et al., 2016).The animals were weighed immediately before slaughter.
The hot carcass weight (HCW) is used to calculate the dressing percentage based on slaughter and empty body weights.After removing the weight of the head, thorax, abdomen, pelvic cavity contents, and legs below the hock and knee joints, the HCW is determined.After severing the vertebrae between the 12th and 13th ribs, the rib-eye muscle area (REMA) is sketched on a transparent plastic grid and measured (Calnan et al., 2014;Williams, 2002).The sum of the tongue, heart, liver, bile, kidney, empty gut, omental fat, heart fat, and kidney fat is used to compute the proportion of total edible offal components (TEOC).Head without tongue, blood, bladder, lung with esophagus and trachea, stomach content, spleen, skin, and feet are total nonedible offal components (TNOC).By deducting the gut content from the slaughter weight, the empty body weight (EBW) is derived.The dressing percentage (DP) is computed using the Gilmour et al. (1994) formula.

Feed conversion efficiency (FCE) =
Average daily body weight gain (g) Average daily feed intake (g)

| Partial budget analysis
The study investigated the economic efficiency of feeding indigenous sheep in Dawuro, a basic diet of native grass hay, 100 g ground maize, and DDLM at varying levels using the technique indicated by Upton (1979).The research entailed determining the total variable cost (TVC) and return on sale.The purchasing price of each lamb was estimated by dealers from a nearby market, and the selling price was estimated in the same manner before slaughtering took place.
The accuracy of weight measurements for sheep was tested in four local marketplaces.Total return (TR) was calculated by subtracting the selling and purchase prices for each lamb.Feed prices were calculated by multiplying the total feed intake for 90 days by market prices since purchase (Fitwi & Tadesse, 2013).The cost of dawridamaa leaf obtained from volunteers was also taken into account.
When acquiring feed, the current price of feed, transportation and labor costs were all taken into account.Net return (NR) was also computed as the amount of money remaining after subtracting total variable cost (TVC) from total returns (TRs).Similarly, the change in net return (∆NR) was determined by subtracting the change in total return (∆TR) from the change in total variable costs (∆TVC).
The percentage marginal rate of return (MRR), which measures the increase in net return (∆NR) associated with each additional unit of expenditure (∆TVC), was calculated as:

| Statistical analysis
Data were analyzed using the General Linear Model (GLM) procedure of SAS 9.3.Fisher's least significant difference (LSD) test was used to compare treatment means, and the values were considered at 5% probability (Gebrekidan et al., 2019).Therefore, the model employed for data analysis: Where: Y ij = response variable; μ = overall mean; t i = ith treatment effect; b j = jth block effect; and e ij = ijth random error.

| Body weight gain and feed conversion efficiency
The A positive ADG (15 g/day) in control animals could be attributable to grass hay and ground maize meeting the minimal need, even with slight development (McDonald et al., 2002).On the other hand, the sheep experienced superior BWC and ADG at T4. Furthermore, changes in BWC and ADG among treatments in the current investigation could be attributed to differences in daily DM consumption and feed digestibility (McDonald et al., 2011).
The FCE of supplemented animals ranged from 0.066 to 0.089 in the current study, which is comparable to the reports (0.06-0.13) by Kiflay et al. (2014) and Tagaynesh (2014).Feed conversion efficiency gains with DDLM supplementation were associated with increased CP intake and digestibility, suggesting that nutritional availability for growth in supplemented sheep was increased.

TA B L E 2
The effect of supplementing different levels of dawri-damaa (DDLM) on body weight change of the experimental sheep during a 90-day feeding trial.
With the exception of the 40th and 90th days, the trend of weight changes across feeding trial days (Figure 1) demonstrated that all sheep across control treatments showed slight body weight gain up to the 90th day.This could be related to poor nutritional composition, specifically the lack of CP in the basal diet to promote optimal growth, as well as increased demand for nutrients for met-   According to Alexandre et al. (2008) and Salo et al. (2016), as slaughter body weight increased, so did HCW.Thus, the higher carcass production reported in supplemented animals is compatible with higher ADG, most likely due to the usage of forage legumes and the function of higher protein turnover in the muscle (Anderson et al., 2005).

| Characteristics of main carcass components
As the rib-eye muscle area (REMA) increases, so does the amount of muscle in the carcass, and the yield grade (USDA, 2009).
A REMA at T1 was 9.1 cm 2 , and the undersupplemented diet was 12.3-14.2cm 2 , which was greater than the 7.4-12.6cm 2 reported by Dejen (2011)  On DPEBW and DPSBW, there was no significant difference (p > .05) between supplemented and nonsupplemented animals (Mechaele, 2018;Mengistu, 2016;Teklu et al., 2017;Wondimagegn, 2012).The dressing percentage is influenced by the animal's gut fill on an SBW and EBW basis.For example, animals in the control group had lower DPSBW% and DPEBW%, whereas animals in the supplemented groups had higher magnitudes due to the consequences of higher levels of nutrition and nutrient utilization in tissue development of the rams (Taylor & Murray, 1991) and breed of the rams (Devendra & Burns, 1983;McDonald et al., 2002).
The study found that supplementing sheep with DDLM resulted in increased body weight, average daily gain, and feed conversion rate.The three doses of Dawri-damma supplementation (30%, 50%, and 70%) resulted in daily increases of 51.4 g, 68.0 g, and 83.8 g, respectively, which outperformed the national meat production average of 50.0 g per animal per day (Melaku & Betsha, 2008) and were significantly higher than those observed in lambs fed a basal diet of 15.0 g in this study.The carcass characteristics, including SBW, EBW, and HCW, were also significantly influenced for the DDLMsupplemented groups compared to the control treatment.
This study demonstrates that adding shrubs, herbs, and legumes, such as DDLM, to a grazing system improves the body size and productivity of local sheep.The values obtained for the relevant variables were greater than the control diets for SBW, EBW, and HCW values, indicating that DDLM is a good supplement in some accessible locations that it is suited for sheep feed.

| Edible offal
Table 4 shows the results of the influence of varied levels of DDLM supplementation on edible offal components of the experimental sheep.The study found that the kidney, tail, reticulo-rumen, omasum, abomasum, small intestine, total fat, and bile were significantly different (p < .05) between the groups fed T1, T2, T3, and T4.However, the liver, heart, tongue, and large intestine were not significantly different (p > .05).The groups fed T2, T3, and T4 had no significant difference (p > .05) in the tail, omasum, abomasum, and small intestine compared to each other, but all were significantly higher than the group fed T1.The bulk of the edible and economically relevant offal components (TEOC) was significantly altered by DDLM supplementation (p < .05).
According to Richardson et al. (2004), noncarcass components contribute 5% of the variation in feeding efficiency.The grand mean of total edible and economically relevant offal components (TEOC) for supplemented lambs in the current study ranged from 3.75 to 4.08 kg.This result is comparable to the value of 3.74-4.16kg reported for Horro sheep (Chala et al., 2019), higher than the 3.2 kg reported for Tigray highland sheep supplemented with cottonseed meal (Amare et al., 2009), but lower than the 4.3-5.4kg reported for Begait sheep fed grass hay and supplemented with various levels of concentrate mixture (Kibrom, 2018).
It is challenging to compare the TEOC of one breed/type to another because each breed has its own characteristic feature for corresponding metrics, which can be modified by age, sex, plane of nutrition, breed, and other associated factors.Furthermore, significant variances may be linked to the method of edible and nonedible noncarcass component classification, which is more or less subjective to one's tradition, beliefs, culture, and preferences (Getahun, 2001).In general, increasing the amount of DDLM added to the basal diet of native grass improved the total quantity of edible offal contents.

| Nonedible offal
The effect of varying levels of DDLM supplementation on nonedible offal components of the experimental sheep is presented in Table 5.The majority of the nonedible carcass components were unaffected by the various doses of supplementation (p > .05).
Giblets, such as lung with trachea, skin, feet, and gut content, on the other hand, responded positively (p < .05) to DDLM administration, with no significant difference between supplementation doses.In general, total nonedible giblet was significantly higher (p < .05) in groups fed varying levels of DDLM supplementation, consistent with the findings of Chala et al. (2019) for Horro sheep.Skin weight acquired from animals fed a control diet may be attributed to insufficient SBW, which is correlated with skin (Mohammed & Yagoub, 2016).
There was no significant difference between all the treatment groups in mean weight of blood and spleen (p > .05).Because the spleen stores blood to release during stressful conditions, the volume of blood on the animal's body has a positive relationship with the size of the spleen.
Although not affected by supplementation, the decreased spleen size of the T1 groups could be attributed to a concurrent decline in blood weight.Treatment 1 had the lowest value for lung with trachea and feet, which could be related to the weight of sheep after slaughter.The higher subcutaneous layer fat storage of sheep may explain the difference in skin weight (Lawrence et al., 2012).
Unsupplemented lambs' gut contents differed due to a longer retention time of ingested feed in the gastro-intestinal tract (Pond et al., 1995), lower degradability and insufficient nutrient supply (Mahgoub et al., 2000), and a decrease in dietary energy level (Yagoub & Babiker, 2008).Gut content was also linked to total Trends in body weight changes of local growing lambs in Dawuro-fed native grass hay supplemented with different levels of dawri-damaa leaf meal during a 90-day feeding period.

| Correlation between body weight gain and carcass parameters
The correlation between ADG, HCW, TEOC, and dressing percentage on the basis of slaughter and empty body weight (SBW and SBW) is presented in A research piece assessing the plant's nutritional value suggested P. schimperiana's potential supplementation as a protein source for animal feed (Kochare et al., 2023;Woretaw et al., 2022).
Other researches also revealed that, in comparison to grazing lambs, lambs finished in a feedlot or with supplementation under extensive systems grow more quickly, reach target weights more rapidly, and produce larger carcass weights (De Brito et al., 2017;Jimenez et al., 2019).

| Partial budget analysis
According to the study, the purchasing costs of lambs across each treatment were essentially identical, as indicated in Table 7.
However, the cost of hay declined with increasing degree of supplementation while overall feed cost increased, so the total cost of production increased with increasing level of supplementation.
Thus, the highest cost (ETB 437.61) was seen among the supplemented, and the best selling price (ETB 1634.61) was received for the lambs fed on T4.Similarly, the total return (TR) and net return (NR) were higher because the lambs were given the maximum level of supplement.This means that higher production costs may have resulted in a higher total return per animal.In general, the economic return of the trial was revealed to be mostly determined by feed expenses, purchasing and selling prices of the experimental sheep.
In this study, the net return (NR) of sheep at T1 is ETB +68.12, indicating that no economic loss was seen when no DDLM was supplemented.The difference in price between control and treated lambs was attributed to differences in BWC of the lambs in each treatment, which was a function of feed quality differences and hence greater FCE.In general, lambs with higher nutrient intake had higher ADG, which resulted in a higher sales price and a larger net return.
abolic reactions.Those in the supplemented group, on the other hand, experienced continuous increases in body weight.Moreover, the rate of weight change in supplemented lambs (T4 > T3 > T2) might be related to the rate of increased CP and ME consumption and the trend of increasing digestibility coefficient.Nevertheless, all treatment levels improved FBW, ADG, and FCE in the current study, indicating that the comparative nutritional content of DDLM feed used in the current study could be supplemented to local lambs fed with poor quality feed resources.

Figure 2
Figure2depicts the effect of ADG on CP consumption of local lambs fed experimental diets.In fact, nutrient contribution was critical in lamb development parameters, while the influence of CP intake on daily live weight gain is significant.The current investigation found a positive and linear correlation (p < .05) between ADG and total CP intake (r 2 = 0.73).This shows that the average daily gain of lambs fed native grass hay with 100 g ground maize supplemented with varied amounts of DDLM is 73% dependent on total CP consumption.Abuye et al. (2018) found r 2 = 0.57, whereasEmebet (2008) andDereje (2012) reported r 2 = 0.78 and 0.76, respectively, which are in line with the current study's findings.This study suggests that supplementing local lambs fed with poor quality feed resources with DDLM feed could significantly improve body weight, average daily gain, and feed conversion efficiency.These findings have implications for enhancing the nutritional content of sheep diets and promoting optimal growth in sheep production systems.
Regression of average daily gain (ADG) over crude protein (CP) intake of Dawuro local lambs fed native grass hay supplemented with different levels of dawri-damaa leaf meal during a 90-day feeding period.nonedibleoffal content (TNOC), which was lower in supplemented sheep than in control (T1) Begait sheep(Abraham, 2019).
Experimental diets allocated for lambs during field trial period.
percentage = Hot carcass weight Slaughter body weight × 100 or = Hot carcass weight Empty body weight × 100 TA B L E 1

Table 6 .
Average daily gain was shown to be Main carcass components of Dawuro local sheep fed grass hay and supplemented with different levels of dawri-damaa leaf meal (DDLM).